[groff] 25/29: src/libs/libgroff/string.cpp: Check malloc return.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 36edfbadb0edf858d638cd2ed3c793566e545789
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Apr 26 11:12:54 2022 +1000

    src/libs/libgroff/string.cpp: Check malloc return.
    
    * src/libs/libgroff/string.cpp (string::extract): Check return value of
      `malloc()` for nullity, and only poke into the buffer returned if it
      is valid.  Discovered while troubleshooting Savannah #62366.
    
    Also update editor aid comments; drop old-style Emacs file-local
    variable setting.
---
 ChangeLog                    |  7 +++++++
 src/libs/libgroff/string.cpp | 18 ++++++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 208c4104..a82860f8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2022-04-26  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/libs/libgroff/string.cpp (string::extract): Check return
+       value of `malloc()` for nullity, and only poke into the buffer
+       returned if it is valid.  Discovered while troubleshooting
+       Savannah #62366.
+
 2022-04-23  Bertrand Garrigues <bertrand.garrigues@laposte.net>
 
        gnulib: replace non-recursive-gnulib-prefix-hack with
diff --git a/src/libs/libgroff/string.cpp b/src/libs/libgroff/string.cpp
index 2392d16e..33c0565c 100644
--- a/src/libs/libgroff/string.cpp
+++ b/src/libs/libgroff/string.cpp
@@ -1,4 +1,3 @@
-// -*- C++ -*-
 /* Copyright (C) 1989-2020 Free Software Foundation, Inc.
      Written by James Clark (jjc@jclark.com)
 
@@ -293,11 +292,13 @@ char *string::extract() const
     if (p[i] == '\0')
       nnuls++;
   char *q =(char*)malloc(n + 1 - nnuls);
-  char *r = q;
-  for (i = 0; i < n; i++)
-    if (p[i] != '\0')
-      *r++ = p[i];
-  *r = '\0';
+  if (q != 0 /* nullptr */) {
+    char *r = q;
+    for (i = 0; i < n; i++)
+      if (p[i] != '\0')
+       *r++ = p[i];
+    *r = '\0';
+  }
   return q;
 }
 
@@ -346,3 +347,8 @@ string as_string(int i)
   return string(buf);
 }
 
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72: